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A Real Love For Speed
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Discussion Starter #1 (Edited)
I have a suggestion that just might promote sales and help the customers also.
If Brand “X” Cam Company would make a complete set of cam shafts that had only one or two of the cylinders with the cam lobes on the cam so the customer could install this cam for mock-up to see if this would clear the pistons for his / her application.
These Trial cams could be rented out with a reimbursement IF the customer bought their cam choice from Brand “X” Cam Company. They could rent a selection in the range of profiles that they are considering. Surely they wouldn’t want to keep a cam with only one or two sets of lobs on it. The shaft only needs to be 1/4 length of a full shaft. A deposit that would be refunded would also insure the return of the Mock-Up cams.
I know I would rent some from you if this was an option.

What do you think ?

Boz
 

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I have a suggestion that just might promote sales and help the customers also.
If Brand “X” Cam Company would make a complete set of cam shafts that had only one or two of the cylinders with the cam lobes on the cam so the customer could install this cam for mock-up to see if this would clear the pistons for his / her application.
These Trial cams could be rented out with a reimbursement IF the customer bought their cam choice from Brand “X” Cam Company. They could rent a selection in the range of profiles that they are considering. Surely they wouldn’t want to keep a cam with only one or two sets of lobs on it. A deposit that would be refunded would also insure the return of the Mock-Up cams.
I know I would rent some from you if this was an option.

What do you think ?

Boz
I think I will do it like I always have.
 

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Just because a valve clears a piston when baring an engine over by hand does not mean that it will clear when the engine is running. Temperature changes cause parts to grow while RPM and inertia cause them to "stretch". The only true way to ensure that the application has enough clearance is to measure the distance between the piston and valves. There are several methods to do this most of which can be researched on the internet. The biggest thing is to take your time, make sure your numbers are accurate and do your homework as different parts (i.e materials) can run tighter clearances than others. Good luck on the build.
 

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Just because a valve clears a piston when baring an engine over by hand does not mean that it will clear when the engine is running. Temperature changes cause parts to grow while RPM and inertia cause them to "stretch". The only true way to ensure that the application has enough clearance is to measure the distance between the piston and valves. There are several methods to do this most of which can be researched on the internet. The biggest thing is to take your time, make sure your numbers are accurate and do your homework as different parts (i.e materials) can run tighter clearances than others. Good luck on the build.
Im confused, aren't you still going to check valve to piston clearance before the motor is ever fired? Or are u suggesting check all cylinders clearance?

Another problem I see with this idea is that this would only work for mass produced cam profiles, it'd be useless to use the 1/4 cam idea if u use a 600 lift 1/4 cam to check clearance, and install a 700 lift. Doesn't seem cost effective to make a custom 1/4 cam every time someone orders a custom cam.
 

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A Real Love For Speed
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Discussion Starter #5
Im confused, aren't you still going to check valve to piston clearance before the motor is ever fired? Or are u suggesting check all cylinders clearance?

Another problem I see with this idea is that this would only work for mass produced cam profiles, it'd be useless to use the 1/4 cam idea if u use a 600 lift 1/4 cam to check clearance, and install a 700 lift. Doesn't seem cost effective to make a custom 1/4 cam every time someone orders a custom cam.
You are right it would be useless to make the ¼ length mock-up cam on custom grinds. Those who do order custom cams already know what will fit. They have mocked up their engine and know exactly what they want. I was intending those who are first time builders or those who are changing the whole set up. Stroke, Compression height & dome cc’s & combustion chamber volume. Checking Cam advance piston to valve clearance during mock up. These would be for those pushing it to the limit on valve lift. I agree this isn’t for everybody and if you have a system that works then stick with it.
These mock-up cams were targeted towards those who do not have a starting point or a system that works for them. Not everybody has a buddy that has a old cam to check his P/V clearances or the clams to have the experts to do it right for them.
Besides, I said I have an Idea. I didn’t say it was a good idea.
Just throwing something out to see if it gets shot down or not. :battle219:
Boz
 

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Boz, I don't think your brillant idea would work to well. YOU may be the ONLY person I know that would buy a cam because it "clears: his pistons, or even avoid a cam because it doesn't.

I personally buy the cam the engine wants, not what I want, or what "clears" my pistons.

I assume you are one that picks the biggest cam that fits?

BTW, I don't recommend you try suggesting this to a cam grinder.



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A Real Love For Speed
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Discussion Starter #7 (Edited)
Boz, I don't think your brillant idea would work to well. YOU may be the ONLY person I know that would buy a cam because it "clears: his pistons, or even avoid a cam because it doesn't.

I personally buy the cam the engine wants, not what I want, or what "clears" my pistons.

I assume you are one that picks the biggest cam that fits?

BTW, I don't recommend you try suggesting this to a cam grinder.

First of all never assume.
And I am not trying to just throw the largest cam I can at this motor.
Just one big enough to make use of the cube’s I’ve chosen. If you really want to give some intelligent advice then will you please let me know What lift cam you would think my 540 ci 14.2:1 comp. 48 cc Domed pistons would want? Could you possibly pass on a name of somebody that could suggest a cam profile? I have been asking for help and so far only one man has told me that the .700” lift cam should fit. But I was the one that suggested the cam lift. Obviously I don’t know what is needed. But so far no recommendation on what lift to use.
Thanks for your input.
Boz
 

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Put clay on top of piston and turn motor. Then you will know how much room you have.
 

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"BOATLESS"
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First of all never assume.
And I am not trying to just throw the largest cam I can at this motor.
Just one big enough to make use of the cube’s I’ve chosen. If you really want to give some intelligent advise then will you please let me know What lift cam you would think my 540 ci 14.2:1 comp. 48 cc Domed pistons would want? Could you possibly pass on a name of somebody that could suggest a cam profile? I have been asking for help and so far only one man has told me that the .700” lift cam should fit. But I was the one that suggested the cam lift. Obviously I don’t know what is needed. But so far no recommendation on what lift to use.
Thanks for your input.
Boz
That’s just how GN7 is. From what I’ve read on these forums he is a VERY knowledgeable guy when it comes to BBC's.
He can help you but you got to get through his sarcasm first!.
:D
 

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That’s just how GN7 is. From what I’ve read on these forums he is a VERY knowledgeable guy when it comes to BBC's.
He can help you but you got to get through his sarcasm first!.
:D
I wasn't being sarcastic. I simply do not get the idea of a "mock up" cam. You cam the engine, and you MAKE the thing work. If you don't care to fly cut the pistons to make the REQUIRED can work, then you appearently are willing to leave power on the table. Most modern pistons will clear whatever cam 90% of the non race boats need anyway. Most race engine builders are not concerned with fly cutting pistons to make the RIGHT cam work in needed.


First of all never assume.
And I am not trying to just throw the largest cam I can at this motor.
Just one big enough to make use of the cube’s I’ve chosen. If you really want to give some intelligent advise then will you please let me know What lift cam you would think my 540 ci 14.2:1 comp. 48 cc Domed pistons would want? Could you possibly pass on a name of somebody that could suggest a cam profile? I have been asking for help and so far only one man has told me that the .700” lift cam should fit. But I was the one that suggested the cam lift. Obviously I don’t know what is needed. But so far no recommendation on what lift to use.
Thanks for your input.
Boz
First, lift is never the problem, duration, LSA and installed intake centerline are. I have a .775 cam that clears stock off the shelf JE pistons, and a .720 that requires fly cutting the same piston, and both cams are ground by the same company. Others that clear the intake fine, but the exhaust needs flycutting. But I never changed my mind about the cam because it required cutting the pistons.
Did you ever consider the effect the rod ratio has on the valve clearance with a given camshaft?
Not to mention how far in the hole the piston is at TDC. If the heads are 24* or 26*, if they have a 2.19, 2.25, or 2.30 intake valve.

So I recommend a cam and the pistons need fly cutting and then you're pissed off because you wanted a cam that "cleared"
Way to many varibles to say what will and will not clear unless you're more than willing to leave some power on the table due to a "safe guess", not whats RIGHT!
1/4 Race cam! :wink2:
That would be my "safe guess":))THumbsUp



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steelcomp was here
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I have a suggestion that just might promote sales and help the customers also.
If Brand “X” Cam Company would make a complete set of cam shafts that had only one or two of the cylinders with the cam lobes on the cam so the customer could install this cam for mock-up to see if this would clear the pistons for his / her application.
These Trial cams could be rented out with a reimbursement IF the customer bought their cam choice from Brand “X” Cam Company. They could rent a selection in the range of profiles that they are considering. Surely they wouldn’t want to keep a cam with only one or two sets of lobs on it. The shaft only needs to be 1/4 length of a full shaft. A deposit that would be refunded would also insure the return of the Mock-Up cams.
I know I would rent some from you if this was an option.

What do you think ?

Boz
Boz, there's really no market for this. I understand your thinking, but the fact is, there are just too many different cam profiles for this to be of any real practicality. Cam cores are expensive and no one is going to take the time to grind four different grinds on a cam, then cut it up, face the front journal, drill it and tap it for the timing set, etc. etc., just to set it on the shelf and "hope" someone is going to rent it. Also, as was said earlier, the engine needs the cam it needs...it's up to the engine builder to accomodate the cam as far as making sure things clear. When you run into valve/piston clearance issues, it's usually an upper-level build and the engine builder should know this ahead of time and prepare for it. Besides, if the cam doesn't clear for some reason, you don't change the cam, you correct the clearance -if- you're doing it right. ;)
JMO
 

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First of all never assume.
And I am not trying to just throw the largest cam I can at this motor.
Just one big enough to make use of the cube’s I’ve chosen. If you really want to give some intelligent advise then will you please let me know What lift cam you would think my 540 ci 14.2:1 comp. 48 cc Domed pistons would want? Could you possibly pass on a name of somebody that could suggest a cam profile? I have been asking for help and so far only one man has told me that the .700” lift cam should fit. But I was the one that suggested the cam lift. Obviously I don’t know what is needed. But so far no recommendation on what lift to use.
Thanks for your input.
Boz
Boz, there's really no market for this. I understand your thinking, but the fact is, there are just too many different cam profiles for this to be of any real practicality. Cam cores are expensive and no one is going to take the time to grind four different grinds on a cam, then cut it up, face the front journal, drill it and tap it for the timing set, etc. etc., just to set it on the shelf and "hope" someone is going to rent it. Also, as was said earlier, the engine needs the cam it needs...it's up to the engine builder to accomodate the cam as far as making sure things clear. When you run into valve/piston clearance issues, it's usually an upper-level build and the engine builder should know this ahead of time and prepare for it. Besides, if the cam doesn't clear for some reason, you don't change the cam, you correct the clearance -if- you're doing it right. ;)
JMO
Damn you have become such a SMOOTH talker since your relocation. Did Chris send you off for some etiquette training?



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Boz, there's really no market for this. I understand your thinking, but the fact is, there are just too many different cam profiles for this to be of any real practicality. Cam cores are expensive and no one is going to take the time to grind four different grinds on a cam, then cut it up, face the front journal, drill it and tap it for the timing set, etc. etc., just to set it on the shelf and "hope" someone is going to rent it. Also, as was said earlier, the engine needs the cam it needs...it's up to the engine builder to accomodate the cam as far as making sure things clear. When you run into valve/piston clearance issues, it's usually an upper-level build and the engine builder should know this ahead of time and prepare for it. Besides, if the cam doesn't clear for some reason, you don't change the cam, you correct the clearance -if- you're doing it right. ;)
JMO
Ya don't need to use a cam core and then cut it up.:duh:You could make out of alum or even some plastics.It could be a throw away deal.We do it all the time on mockup of aircraft parts.The process is called Stereolithography.Parts are molded in a machine to close tolerances using a solid model from a Cad program.:thumb:
.Not in ISKY's 80 year old cam grinder.:))eek:))
 

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Ya don't need to use a cam core and then cut it up.:duh:You could make out of alum or even some plastics.It could be a throw away deal.We do it all the time on mockup aircraft parts. :thumb:
It could be cast plastic. Thats not the point. You don't chose a cam because it doesn't create P-V clearence problems. Like Steel and I said, you don't get into these issues unless your considering using a pretty long cam, and if that the case you should REALLY be using the RIGHT cam, not the one that "fits" Thats the craziest thing I have ever heard of when you get to that level of cam timing. Its not like the guy is using OEM stock pistons. If he has P-V clearence issues using aftermaket pistons, that cam is pretty freek'n long, or has one tight ass LSA or both. If thats the case, then you fix the problem, and not by switching cams.



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A Real Love For Speed
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Discussion Starter #17
Ya don't need to use a cam core and then cut it up.:duh:You could make out of alum or even some plastics.It could be a throw away deal.We do it all the time on mockup of aircraft parts.The process is called Stereolithography.Parts are molded a machine to close tolerances using a solid model from a Cad program.:thumb:
.Not in ISKY's 80 year old cam grinder.:))eek:))

This is how it was done in the Gas Turbine engines I worked on.
And no, It doesn’t sound to be practical when you conceder all the different profiles offered.
Boz
 

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First of all never assume.
And I am not trying to just throw the largest cam I can at this motor.
Just one big enough to make use of the cube’s I’ve chosen. If you really want to give some intelligent advise then will you please let me know What lift cam you would think my 540 ci 14.2:1 comp. 48 cc Domed pistons would want? Could you possibly pass on a name of somebody that could suggest a cam profile? I have been asking for help and so far only one man has told me that the .700” lift cam should fit. But I was the one that suggested the cam lift. Obviously I don’t know what is needed. But so far no recommendation on what lift to use.
Thanks for your input.
Boz

Jerry Cantrell 619-297-0227 Schneider racing cams!
 

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steelcomp was here
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Ya don't need to use a cam core and then cut it up.:duh:You could make out of alum or even some plastics.It could be a throw away deal.We do it all the time on mockup of aircraft parts.The process is called Stereolithography.Parts are molded a machine to close tolerances using a solid model from a Cad program.:thumb:
.Not in ISKY's 80 year old cam grinder.:))eek:))
Yeah...whip out a few of those for me with accurate cam lobes on them. ;)
I'm pretty familiar with StereoLith and I don't think it would work as easily as you think, but it's not a bad idea and I wouldn't completely dismiss it -if the idea was practical to stat. Here's the other thing, though...if a guy is checking valve piston clearance with just checking springs, IMO he's fooling himself. Ultimately, I want to final-check everything with running springs assembled on the heads. If you have enough cam to be worrying about valve/piston, then I'd bet you're going to have too much spring to use a plastic or aluminum "test" core. Again, JMO.
 

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Yeah...whip out a few of those for me with accurate cam lobes on them. ;)
I'm pretty familiar with StereoLith and I don't think it would work as easily as you think, but it's not a bad idea and I wouldn't completely dismiss it -if the idea was practical to stat. Here's the other thing, though...if a guy is checking valve piston clearance with just checking springs, IMO he's fooling himself. Ultimately, I want to final-check everything with running springs assembled on the heads. If you have enough cam to be worrying about valve/piston, then I'd bet you're going to have too much spring to use a plastic or aluminum "test" core. Again, JMO.
The only way you are going to get the accuracy of a camshaft is to grind it. If there was a fast easier way to do it, they'd be doing it.

besides, which is REALLY more important here. If it fits and clears everything, or what it SOUNDS like? Comp Cams does have recordings on their website you can listen to, to help you chose the right cam for YOU, screw what the engine wants, it sounds bad ass.
Whatever it takes to move product I guess.



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